Aromatic polyesters, such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT), are widely used in fiber forming applications. However, the use of aromatic polyesters in nonwoven applications has been hindered by the inability of aromatic polyesters to be thermally bonded at relatively moderate bonding temperatures, such as those used for polypropylene, because polyesters have relatively high melting points.
Aliphatic copolyesters, which may or may not have an aromatic structure, typically have much lower melting points than aromatic polyesters. The melting points of aliphatic copolyesters are in about the same range as those of polyolefins. Similarly, aromatic copolyesters also melt at lower temperatures than typical aromatic polyesters. However, aliphatic copolyesters and aromatic copolyesters typically have less desirable fiber forming properties than aromatic polyesters.
There is a need or desire for compositions having favorable fiber forming properties as well as the ability to be thermally bonded at relatively moderate bonding temperatures.